Moon

A new chapter has opened in my research career; in the fall of 2011 I began working with the Gravity Recovery and Interior Laboratory (GRAIL) Mission.
Drawing from my experience in the scientific analysis of a broad range of visible and infrared remote sensing data, I am developing a lunar research program to investigate the elemental and mineralogical composition, photometric and physical properties, impact and volcanic processes, and history of the lunar surface with the goal of developing new insights into the Moon's evolutionary history, using a collection of new data returned by recent spacecraft investigations.

More specifically, the research I propose involves the integrated analysis of recent data from a variety of investigations that include the Moon Mineral Mapper (M3) spectrometer,
the Lunar Reconnaissance Orbiter (LRO) Diviner radiometer, the LRO Lunar Orbiter Laser Altimeter (LOLA), and the LRO Camera (LROC). While most of these data are publicly available, I will collaborate with members of each of the teams, primarily through relationships developed through my Mars-related research, as well as in concert with researchers at MIT.

Mars

My early scientific career was focused on the exploration of Mars.
For my undergraduate honors thesis at the University of Arizona, I compiled measurements of the mean propagation direction of dust devils on Mars from Mars Orbital Camera (MOC) imaging data. Comparing this to global circulation models, I identified a correlation between dust devil trails and mean wind directions during southern summer, showing the formation of dust devils has a seasonal dependence [Soderblom, 2000]. In my research at Cornell as a graduate student, I used Hubble Space Telescope (HST) Wide-Field Planetary Camera (WFPC) and WFPC2 data to model and map the visible to near-infrared photometric properties of the Martian surface at regional scales [Soderblom et al., 2006].

Much of my doctoral work at Cornell involved exploring Mars with landed instruments aboard the Mars Exploration Rovers (MER).
I have investigated the mineralogy [Bell et al., 2004a, 2004b; Farrand et al., 2006, 2007] and the spectro-photometric properties [Johnson et al., 2006a, 2006b, 2008; Soderblom 2007] of the Martian surface with multispectral imaging data from the MER Panoramic Camera (Pancam) instrument. I provided tight constraints on the airborne-dust size distribution [Soderblom, 2007], by exploiting a unique character of the MER Navigation cameras (these camera systems are effectively free of scattered light) to measure the atmospheric phase function at very small scattering angles (very close to the solar disk), not previously attainable.
By observing the Martian sky during the onset and dissipation of a very massive dust storm, such analyses allow determination of the sizes of dust grains suspended in the Martian atmosphere during such massive storms, as well as how these particles settle out following such an event [Soderblom et al., in preparation]. I am also working with MER Navigation Camera (Navcam) data to model the photometric properties of the Martian surface. This investigation is unique, in that the spectral bandpass of the MER navigation camera is nearly identical to the Mars Express High Resolution Stereo Camera (HRSC) photometry channels, enabling collaborative MER/Mars Express investigations.

Titan

For the past five years, I have focused on the study of Titan’s surface composition, geology, history, and photometric properties using data acquired by the Cassini spacecraft.
With Cassini Visual and Infrared Mapping Spectrometer (VIMS) data, I have modeled the radiometric properties of liquid bodies on Titan, providing constraints on the composition [Brown et al. 2008] and physical state of these lakes [Brown et al., 2008; Stephan et al., 2010; Soderblom et al., 2008]. Detailed modeling of near infrared specular reflections from Titan’s hydrocarbon lakes further restricts their physical properties (i.e. index of refraction) and thereby composition [Soderblom et al., 2012]. I have investigated and published on a variety of geologic processes and features on Titan, including impact structures [Soderblom et al., 2010], cryovolcanoes [L. Soderblom et al., 2009], and pluvial and fluvial erosional landforms [Jaumann et al., 2008; Barnes et al., 2009; Soderblom et al., 2010] using Cassini VIMS and RADAR data.
I am currently involved in a number of research projects, including mapping the distribution of liquids on Titan's surface through the detection of specular reflections, constraining the composition and distribution of organics on Titan's surface, and investigating the opacity of Titan's atmosphere in the visible and near infrared. I also have taken an active role in the Cassini mission. In 2011, I became an official member of the Cassini Project, being selected as a Cassini Participating Scientist in the project's first call for Participating Scientists. I also represent VIMS in the Cassini Cross Discipline Target Working Team, one of the teams responsible for negotiating Cassini observations. I have organized and hosted the Cassini Titan Surface Workshop, a forum developed to share new and unpublished results from the Cassini investigation of Titan.

Mission Development and Operations

In addition to my research in analyzing telescopic and spacecraft data, I have been extremely active in the development and operations of planetary spacecraft missions.
While at Cornell, I participated in the end-to-end implementation, calibration, flight operations, and scientific analysis of MER Pancam multispectral imaging investigation. I also developed an absolute radiometric calibration for the MER navigation camera systems [Soderblom et al., 2008], enabling the studies conducted using these data that I mentioned above; these data, so calibrated, are now available as part of the MER data releases to the NASA Planetary Data System

In 2007 I was invited to join NASA’s Science Definition Team for the Titan Saturn System Mission (TSSM) study, a NASA-ESA study to define one of the next flagship missions. I was instrumental in developing the scientific goals upon which further exploration of Titan should be based and established the measurement requirements required to address these questions.
I took the lead role in defining the imaging spectrometer concept published in the TSSM final report. My research in developing this concept led an independent instrument development effort: a collaborative effort between the University of Arizona and JPL. That development ultimately resulted in a near-infrared camera designed to image Titan's surface at high spatial resolution that was included as part of the payload on a mission to explore Titan and Enceladus, submitted by Christophe Sotin to the Discover 2010 AO.
I am now working with JPL to further refine the design of this instrument through a combination of efforts, enabled by JPL internal funding and through a proposal that I recently submitted as PI to NASA's Planetary Instrument Definition and Development Program—these efforts are to prepare such an instrument for a future Discovery proposal. I am also a member of two separate teams that are developing instruments for the Europa Jupiter System Mission (EJSM).